Varnish for producing mat surfaces.



ADOLF'HERBIG, OF COLOGNE-BICKENDORF, GERMANY.

VARNISH FOR PRODUCING MAT SURFACES.

Specification of Letters Patent.

Patented July so, 1907.

Application filed April 3, 1906. gflrifil 3 To all whom it may concern:

Be it known that I, Anew Hhmno, a subject of the German Emperor, and a resident of Oolognediicken doll, in the ljiingdoin ol Prussia, German lthnpiro, and Whose post-ollice address is 2H) Rochusstrasse, same place, have invented new and useful Improvements in Varnishes for Producing l\lat Surl'a.ces a-nd in Processes for Making'same, of which the following is a lull, clear, and exact specification.

Varnishes hitherto used for producing coatings having a mat surface consist either oi wax, ceresin, ozokerite, parallin or other solid hydrocarln'm suspended in a fatty oil varnish or of a mechanical mixture of a fatty oil varnish with an indifferent material, like starch, lino sand, certain silicates, gypsum or other inorganic so-ealled filling materials. These two kinds of mat varnishes leave much to be desired in that they produce very imperl'ect results in practice In the first kind the wax, cercsin or other hydrocarbon takes no part in the peculiar drying and consoquent hardening process, because of its slight chemical activity, and there is also the objection that during" the progressive d rying of the oil varnish the tendency for the latter to dissolve the added matter decreases, so that this matter a(.'(uinulates on the surface of the coating, which thus acquires the property of becoming sticky andv soil; at temperatures wheroat the added matter begins to become solt and fluid. On this account mat varnishes of this kind cannot be used for ordinary furniture, if a. good result is to be obtained. The varnishes ol the second kind, so far as those containing starch or starchy materials are com-crnml, have the disadvantage that they cannot withstanid contact with water without the swelling of the starch. Shots ensue and owing to the unequal expansion of the swollen starch and oil varnish the whole coating cracks and pools oil. The varnishes inade with indil'l' rent filling materials have the like disadvantage, that the filling material and the 'oil varnish surrounding it have an essentially dil'i'orent tendency to take up moisture from the air; on this ac- 'ount coatings ol' such varnishes soon (-i'; ck and become hritllrso that they are not applicable, especially to large surfaces like cabinets or doors.

The present invention depends on the discovery that when a fatty drying oil or a fatty drying (ii varnish is mixed nu-chanimlly with hydrated alumina, the varnish and aluminum compound combine under partial sanoniliralion. llut it is during the drying of the oil or varnish that chemical combination especially occurs between it and the aluminum compound, as the acid wmpouods produced in the varnish by oxidation during the drying have a greater activity than that ol the original oil or varnish and themselves combine with the basic aluminum compound. Evidence of the correctness of llv foregoing statements accrues-from the facts that l tdy during the mechanical mixing of the aluminum compound with the fatty oil varnish, heat is evolved, indicating chemical reaction, and that: the mixture undergoes a considerable change of con-- sistency altera short time. showing that a new CQHlpound is being formed. The dried coating 01' the new compound displays its difference from the oil varnisl' containing indifferent filling materials by yielding the aluminum compound in inmate of combination when. treated with solvents Under fatty drying oils are understood vegetable oils which contain glycerids ol" unsaturated latty acids and which are capable,

when exposed to the oxygen of the air, of forming tenacious skin within a shorter or longer period of time. Under fatty dryingoil varnishes are understood such vegetable oils that are boiled with or without addition of a gum or siccatiye in a; suitable form and which are glyccrids ol" unsaturated acids and Whichpossess the property, when exposed to the oxygen of the air, to lorm a firm tenacious skin. This definition corresponds to the definition given by Lewkowitsch in his standard work.

The mat varnish made according to the invention, unlike tho aforesaid mat varnishes of't he first kind, does not become sticky or show any tendency -to soften; as compared with mat varnishes oi the second kind, it possesses complete homogeneity, whereby it remains elastic and free from cracks; moreover, the aluminum I compound formed not being saponil'iahle, the varnish is not attacked by water at ordinary temperature.

Example. parts of afatty drying oil varnish are ground in known manner with t---]() parts of hydrated alumina, and the strongly thickened product is reduced to the original consistence by addition of a suitable solvent. Such solvents are spirits of turpentine, wood alcohol, the light, distillation products of petroleum and coal-tar, acetone and its homologucs, carbon tetrachlorid, carbon sullid, amyl and other alcohols, acetic esters, nitrohenzene, anilin, and the like. The varnish thus pre 'iared is ready for use.

What l claim is:-

1. The herein described varnish for producing nu s, con, i in: or a mixture 01' :1 fatty dryinghydratt-d alumina.

l. 'llic herein described varnish for producing mat, surtact-s, consisting of a mixture of a fatty drying oil varnish with hydrated alumina.

In testimony, that 1 claim the foregoing as iny invention, I have signed my name in presence of two subscribing oil with wit m sses.

ADOLF IIERBIG.

mat sur- 

